Project Summary/Abstract Although engaging in regular physical activity (PA) plays a critical role in reducing one?s risk for numerous health problems, 4 out of 5 U.S. adults fail to meet national PA guidelines, with underserved groups (low income and racial/ethnic minority groups) having the highest rates of physical inactivity. Developing innovative strategies to motivate underserved groups to initiate PA has become an increasing national priority, but many implementation challenges remain, as evidenced by relatively low levels of program engagement among underserved groups. Increasingly, researchers have begun to show that rather than using a ?one-size-fits all? intervention approach, developing interventions that target specific individual differences in cultural or social-cognitive factors is a highly effective approach for increasing engagement among underserved groups. Broadening this approach in a novel domain, the present research argues that despite an extensive body of research showing that there is substantial variability in the extent to which people?s motivation for initiating PA is guided by autonomous (internally-driven) vs. controlled (externally-driven) reasons, developing interventions that target differences in autonomous vs. controlled motivation has been overlooked as a critical strategy for engaging underserved groups in PA initiation. Integrating results from a preliminary focus group study on PA barriers/facilitators with inactive African Americans and a novel multi-theoretical framework, the proposed research will examine whether matching an intervention to a person?s motivation (autonomous vs. controlled) is a feasible strategy for promoting PA initiation among inactive AA adults, defined as those who engage in < 150 minutes of moderate PA per week. The Developing Real Incentives and Volition for Exercise (DRIVE) project will develop and evaluate two novel interventions: 1) a challenge- focused program that targets greater valuation of PA, competitive excitement, and relatedness through intergroup competition, behavioral skills, and a positive social climate; and 2) a rewards-focused program that targets greater PA enjoyment, competency, and relatedness through incentives, behavioral skills, and structured social support. Drawing from Self-Determination Theory and a growing body of literature showing that incentives promote PA initiation, the present research proposes that a challenge-focused intervention will more effective at engaging people who initiate PA for autonomous (vs. controlled) reasons, whereas a rewards-focused program will be more effective at engaging people who initiate PA for controlled (vs. autonomous) reasons. The study will be conducted in two phases. During Phase 1, the challenge- and rewards-focused programs will be developed [Aim 1]. The feasibility and acceptability of the newly developed interventions will then be tested in a small pilot study (n = 30) and refined based on participants? feedback and preliminary results [Aim 2]. During Phase 2, a small-scale randomized study (n = 150) will be conducted to evaluate whether participants who receive an intervention that is matched to their motivation for PA initiation (Autonomous & Challenge-Focused; Controlled & Rewards-Focused) engage in greater minutes of total PA than those who receive an unmatched intervention (Autonomous & Rewards-Focused; Controlled & Challenge-Focused).